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https://www.readbyqxmd.com/read/28703318/ft-artifacts-and-power-function-resolution-filter-in-fourier-transform-mass-spectrometry
#1
Basem Kanawati, Theresa Bader, Karl-Peter Wanczek, Yan Li, Philippe Schmitt-Kopplin
RATIONALE: Peak picking algorithms in mass spectrometry face the challenge of picking the correct signals from a mass spectrum. In some cases signal wiggles (side lobes) are also chosen in the produced mass list as if they were real signals. Constraints which are defined in such algorithms do not always guarantee wiggle free accurate mass list generation out of raw mass spectra. This problem intensifies with acquisitions, which are accompanied with longer transients. Thus, the problem represents a contemporary issue, which propagates with modern high memory digitizers and exists in both MS and MS/MS spectra...
July 13, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28622319/flicker-electroretinograms-recorded-with-mydriasis-free-reteval-system-before-and-after-cataract-surgery
#2
G Miura, E Sato, S Yamamoto
PurposeThe purpose of this study is to compare the amplitudes and peak times of the flicker electroretinograms (ERGs) recorded before and after cataract surgery with the RETeval system (LKC Technologies, Gaithersburg, MD, USA) from eyes without dilation.Patients and methodsThirty-two eyes of 32 patients (77.3±6.5 years) that had grade 2 Emery-Little nuclear or cortical cataract without any other abnormalities were studied. Flicker ERGs were recorded with the RETeval system under mydriatic-free conditions. Skin electrodes were used to pick-up the ERGs that were elicited by white light delivered at a rate of 28...
June 16, 2017: Eye
https://www.readbyqxmd.com/read/28542374/targeted-box-and-blocks-test-normative-data-and-comparison-to-standard-tests
#3
Kimberly Kontson, Ian Marcus, Barbara Myklebust, Eugene Civillico
BACKGROUND: The Box and Block Test (BBT) is a functional outcome measure that is commonly used across multiple clinical populations due to its benefits of ease and speed of implementation; reliable, objective measurement; and repetition of motion. In this study, we introduce a novel outcome measure called the targeted BBT that allows for the study of initiation, grasping, and transport of objects, and also of object release. These modifications to the existing test may increase the ecological validity of the measure while still retaining the previously stated benefits of the standard BBT...
2017: PloS One
https://www.readbyqxmd.com/read/28520864/from-chromatogram-to-analyte-to-metabolite-how-to-pick-horses-for-courses-from-the-massive-web-resources-for-mass-spectral-plant-metabolomics
#4
Leonardo Perez de Souza, Thomas Naake, Takayuki Tohge, Alisdair R Fernie
The grand challenge currently facing metabolomics is the expansion of the coverage of the metabolome from a minor percentage of the metabolic complement of the cell towards the level of coverage afforded by other post-genomic technologies such as transcriptomics and proteomics. In plants this problem is exacerbated by the sheer diversity of chemicals that constitute the metabolome with the number of metabolites in the plant kingdom generally being considered to be in excess of 200 000. In this review we focus on web-resources that can be exploited in order to improve analyte and ultimately metabolite identification and quantification...
May 17, 2017: GigaScience
https://www.readbyqxmd.com/read/28505421/development-of-high-performance-chemical-isotope-labeling-lc-ms-for-profiling-the-carbonyl-submetabolome
#5
Shuang Zhao, Margot Dawe, Kevin Guo, Liang Li
Metabolites containing a carbonyl group represent several important classes of molecules including various forms of ketones and aldehydes such as steroids and sugars. We report a high-performance chemical isotope labeling (CIL) LC-MS method for profiling the carbonyl submetabolome with high coverage and high accuracy and precision of relative quantification. This method is based on the use of dansylhydrazine (DnsHz) labeling of carbonyl metabolites to change their chemical and physical properties to such an extent that the labeled metabolites can be efficiently separated by reversed phase LC and ionized by electrospray ionization MS...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28449877/two-stage-algorithm-vs-commonly-used-approaches-for-the-suspect-screening-of-complex-environmental-samples-analyzed-via-liquid-chromatography-high-resolution-time-of-flight-mass-spectroscopy-a-test-study
#6
Saer Samanipour, Jose A Baz-Lomba, Nikiforos A Alygizakis, Malcolm J Reid, Nikolaos S Thomaidis, Kevin V Thomas
LC-HR-QTOF-MS recently has become a commonly used approach for the analysis of complex samples. However, identification of small organic molecules in complex samples with the highest level of confidence is a challenging task. Here we report on the implementation of a two stage algorithm for LC-HR-QTOF-MS datasets. We compared the performances of the two stage algorithm, implemented via NIVA_MZ_Analyzer™, with two commonly used approaches (i.e. feature detection and XIC peak picking, implemented via UNIFI by Waters and TASQ by Bruker, respectively) for the suspect analysis of four influent wastewater samples...
April 20, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28438305/cardiovascular-response-to-recreational-hockey-in-middle-aged-men
#7
Zack A Goodman, Scott G Thomas, Robert C Wald, Jack M Goodman
The present study examined the hemodynamic response to recreational pick-up hockey relative to maximal exercise testing in middle-aged men. A total of 23 men with a mean age of 53 ± 7 years were studied. Graded exercise testing on a cycle ergometer determined maximal oxygen consumption, blood pressure (BP), and heart rate (HR). Ambulatory BP and Holter electrocardiographic monitoring was performed during one of their weekly hockey games (mean duration = 45 ± 7.2 minutes): for "On-Ice" responses (PLAY; data recorded while standing immediately after a shift; 8...
April 11, 2017: American Journal of Cardiology
https://www.readbyqxmd.com/read/28371585/validity-of-field-assessments-to-predict-peak-muscle-power-in-preschoolers
#8
Sara King-Dowling, Nicole A Proudfoot, John Cairney, Brian W Timmons
Field-based fitness assessments are time- and cost-efficient. However, no studies to date have reported the predictive value of field-based musculoskeletal fitness assessments in preschoolers. The purpose of this study was to determine the validity of 2 field assessments to predict peak muscle power in preschool-aged children. Four-hundred and nineteen 3- to 5-year olds participated (208 girls, 211 boys; mean age: 4.5 ± 0.9 years). Peak power (PP) was evaluated using a modified 10-s Wingate protocol as the criterion standard...
April 3, 2017: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
https://www.readbyqxmd.com/read/28355412/influence-of-work-pace-on-upper-extremity-kinematics-and-muscle-activity-in-a-short-cycle-repetitive-pick-and-place-task
#9
Tessy Luger, Svend Erik Mathiassen, Divya Srinivasan, Tim Bosch
Objectives: This study investigated the extent to which controlled changes in work pace in a cyclic pick-and-place task influence upper extremity kinematics and muscle activity, and whether an effect depends on working height. Methods: Thirteen participants performed the task for 4 min at each of five work paces ranging from 8 to 12 cycles·min-1 in each of two experimental conditions where the hand was moved horizontally with an average upper arm elevation of 30° and 50°, respectively...
April 1, 2017: Annals of Work Exposures and Health
https://www.readbyqxmd.com/read/28353646/intraguild-predation-dynamics-in-a-lake-ecosystem-based-on-a-coupled-hydrodynamic-ecological-model-the-example-of-lake-kinneret-israel
#10
Vardit Makler-Pick, Matthew R Hipsey, Tamar Zohary, Yohay Carmel, Gideon Gal
The food web of Lake Kinneret contains intraguild predation (IGP). Predatory invertebrates and planktivorous fish both feed on herbivorous zooplankton, while the planktivorous fish also feed on the predatory invertebrates. In this study, a complex mechanistic hydrodynamic-ecological model, coupled to a bioenergetics-based fish population model (DYCD-FISH), was employed with the aim of revealing IGP dynamics. The results indicate that the predation pressure of predatory zooplankton on herbivorous zooplankton varies widely, depending on the season...
March 29, 2017: Biology
https://www.readbyqxmd.com/read/28327092/metax-a-flexible-and-comprehensive-software-for-processing-metabolomics-data
#11
Bo Wen, Zhanlong Mei, Chunwei Zeng, Siqi Liu
BACKGROUND: Non-targeted metabolomics based on mass spectrometry enables high-throughput profiling of the metabolites in a biological sample. The large amount of data generated from mass spectrometry requires intensive computational processing for annotation of mass spectra and identification of metabolites. Computational analysis tools that are fully integrated with multiple functions and are easily operated by users who lack extensive knowledge in programing are needed in this research field...
March 21, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/28295580/specpad-device-independent-nmr-data-visualization-and-processing-based-on-the-novel-dart-programming-language-and-html5-web-technology
#12
Bruno Guigas
SpecPad is a new device-independent software program for the visualization and processing of one- and two-dimensional NMR time domain (FID) and frequency domain (spectrum) data. It is the result of a project to investigate whether the novel programming language DART, in combination with Html5 Web technology, forms a suitable base to write an NMR data evaluation software which runs on modern computing devices such as Android, iOS, and Windows tablets as well as on Windows, Linux, and Mac OS X desktop PCs and notebooks...
March 12, 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/28286574/nontargeted-homologue-series-extraction-from-hyphenated-high-resolution-mass-spectrometry-data
#13
Martin Loos, Heinz Singer
BACKGROUND: A large proportion of polar anthropogenic compounds routinely released into the environment comprises homologue series, i.e., sets of chemicals differing in a repeating chemical unit. Using analytical techniques such as liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS), these compounds are readily measurable as signal sets with characteristic differences in mass and typically retention time. However, and despite such distinct characteristics, no computational approach for the direct, simultaneous and untargeted detection of all such signal sets comprising both LC and HRMS information has to date been presented...
2017: Journal of Cheminformatics
https://www.readbyqxmd.com/read/28213793/automation-of-peak-tracking-analysis-of-stepwise-perturbed-nmr-spectra
#14
Tommaso Banelli, Marco Vuano, Federico Fogolari, Andrea Fusiello, Gennaro Esposito, Alessandra Corazza
We describe a new algorithmic approach able to automatically pick and track the NMR resonances of a large number of 2D NMR spectra acquired during a stepwise variation of a physical parameter. The method has been named Trace in Track (TINT), referring to the idea that a gaussian decomposition traces peaks within the tracks recognised through 3D mathematical morphology. It is capable of determining the evolution of the chemical shifts, intensity and linewidths of each tracked peak.The performances obtained in term of track reconstruction and correct assignment on realistic synthetic spectra were high above 90% when a noise level similar to that of experimental data were considered...
February 17, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28213211/application-of-2d-hplc-coupled-with-principal-component-analysis-to-study-an-industrial-opiate-processing-stream
#15
Paul G Stevenson, Niki K Burns, Stuart D Purcell, Paul S Francis, Neil W Barnett, Fiona Fry, Xavier A Conlan
Principal component analysis (PCA) loading plots were used to elucidate key differences between two-dimensional high performance liquid chromatography (2D-HPLC) fingerprint data from samples collected from stages along the Papaver somniferum industrial process chemistry workflow. Data reduction was completed using a 2D-HPLC peak picking approach as a precursor to chemometric analysis. Using comparisons of the final stages of product extraction as an example, PCA analysis of characteristic 2D-HPLC fingerprints accounted for 84...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28160196/infos-spectrum-fitting-software-for-nmr-analysis
#16
Albert A Smith
Software for fitting of NMR spectra in MATLAB is presented. Spectra are fitted in the frequency domain, using Fourier transformed lineshapes, which are derived using the experimental acquisition and processing parameters. This yields more accurate fits compared to common fitting methods that use Lorentzian or Gaussian functions. Furthermore, a very time-efficient algorithm for calculating and fitting spectra has been developed. The software also performs initial peak picking, followed by subsequent fitting and refinement of the peak list, by iteratively adding and removing peaks to improve the overall fit...
February 3, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28160195/peak-picking-multidimensional-nmr-spectra-with-the-contour-geometry-based-algorithm-cypick
#17
Julia M Würz, Peter Güntert
The automated identification of signals in multidimensional NMR spectra is a challenging task, complicated by signal overlap, noise, and spectral artifacts, for which no universally accepted method is available. Here, we present a new peak picking algorithm, CYPICK, that follows, as far as possible, the manual approach taken by a spectroscopist who analyzes peak patterns in contour plots of the spectrum, but is fully automated. Human visual inspection is replaced by the evaluation of geometric criteria applied to contour lines, such as local extremality, approximate circularity (after appropriate scaling of the spectrum axes), and convexity...
February 3, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28150425/integrated-hptlc-based-methodology-for-the-tracing-of-bioactive-compounds-in-herbal-extracts-employing-multivariate-chemometrics-a-case-study-on-morus-alba
#18
Eliza Chaita, Evagelos Gikas, Nektarios Aligiannis
INTRODUCTION: In drug discovery, bioassay-guided isolation is a well-established procedure, and still the basic approach for the discovery of natural products with desired biological properties. However, in these procedures, the most laborious and time-consuming step is the isolation of the bioactive constituents. A prior identification of the compounds that contribute to the demonstrated activity of the fractions would enable the selection of proper chromatographic techniques and lead to targeted isolation...
March 2017: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/28012801/occurrence-and-variation-of-lipophilic-shellfish-toxins-in-phytoplankton-shellfish-and-seawater-samples-from-the-aquaculture-zone-in-the-yellow-sea-china
#19
Meihui Li, Geng Sun, Jiangbing Qiu, Aifeng Li
Lipophilic shellfish toxins (LSTs) produced by diverse microalgae have become a potential threat to the marine aquaculture industry in coastal regions throughout the world. In this study, phytoplankton, scallop, and seawater samples were collected and monitored in the aquaculture zone of Liuqing Bay located in the coast of Qingdao, Yellow Sea, in 2014 and 2015. Dissolved LSTs in seawater were adsorbed by solid phase adsorption toxin tracking (SPATT) bags and solid phase extraction (SPE) cartridges, respectively...
December 22, 2016: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/27966901/multiplexed-post-experimental-monoisotopic-mass-refinement-mpe-mmr-to-increase-sensitivity-and-accuracy-in-peptide-identifications-from-tandem-mass-spectra-of-cofragmentation
#20
Inamul Hasan Madar, Seung-Ik Ko, Hokeun Kim, Dong-Gi Mun, Sangtae Kim, Richard D Smith, Sang-Won Lee
Mass spectrometry (MS)-based proteomics, which uses high-resolution hybrid mass spectrometers such as the quadrupole-orbitrap mass spectrometer, can yield tens of thousands of tandem mass (MS/MS) spectra of high resolution during a routine bottom-up experiment. Despite being a fundamental and key step in MS-based proteomics, the accurate determination and assignment of precursor monoisotopic masses to the MS/MS spectra remains difficult. The difficulties stem from imperfect isotopic envelopes of precursor ions, inaccurate charge states for precursor ions, and cofragmentation...
December 22, 2016: Analytical Chemistry
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